The effect of compound 48/80 on the carbachol-evoked acid secretion of the isolated mouse stomach.

The aim of the present work was to determine in the isolated mouse stomach whether the depletion of mast cell histamine by compound 48/80 influences the acid secretion, evoked by carbachol. Each effect of carbachol was compared to the effect of histamine (10(-6) M), applied after each carbachol application. After carbachol and histamine, compound 48/80 was applied twice or three times successively; the second and the third application were not able to evoke any secretion. After 48/80, the applications of carbachol and histamine were repeated and their effects compared to those before the applications of compound 48/80. Three concentrations of the compound were used: 20, 100 and 500 micrograms/ml. The lowest concentration of the histamine liberator did not significantly change the response to carbachol, The highest one reduced it but the effect of histamine was reduced, too. Compound 48/80 in concentration 100 micrograms/ml significantly augmented the secretory effect of carbachol. The possible explanation for this effect is that histamine, liberated from mast cells, is taken up by some other cells in the tissue from where it is liberated by carbachol stimulation.